1. Field of the Invention
This invention relates to a means of controlling the muzzle velocity of a projectile, in particular to a means for correcting the muzzle velocity of a projectile fired from an artillery gun.
2. Discussion of the Prior Art
There is a constant military requirement to enhance the accuracy of munitions in order to increase their effectiveness and minimise collateral damage. For projectiles and the like it has been found that dispersion is often much greater in the longitudinal direction, due to discrepancies in the launch velocity, than the dispersion in the transverse direction. Thus, by correcting the deviances in range the accuracy of such munitions can be greatly increased.
One way of correcting the deviances in range is to alter the air resistance of the munition in flight in response to a deviation from some measured trajectory parameter. European Patent specification No. 0 138 942 discloses a course correction system for projectiles which measures the launch velocity, determines the impact point and relays a signal to the munition to activate a braking means on the projectile at an appropriate point. Such braking systems however require the projectile to house the braking means and also the sophisticated communication equipment reducing the available payload volume and increasing the cost of each shell. Further, such correction means always has a negative effect on range.